1. Field of the Invention
The present invention relates to a method for manufacturing a three elemental diffusion barrier layer for a semiconductor metal wiring, and more particularly, to a method for manufacturing the same which is comprised of a nitride layer of refractory metal or a chemical compound of refractory metal and a Nitrogen (N.sub.2) as a primary material.
2. Description of the Related Art
Generally, an ideal diffusion barrier layer in a manufacturing process of forming a semiconductor metal wiring should not only physically and chemically be stable at the interface between a metal and Silicon (Si) or a metal and a Silicon Oxide (SiO.sub.2) due to the lower reactivity relative to the underlying layer, but also be an amorphous structure in order to avoid the diffusion from a grain boundary at a high temperature. Especially, in order to use a chemical compound as the diffusion barrier layer for Copper (Cu) which easily initiates the diffusion at a relatively low temperature, it has been presently introduced that an amorphous type of two elemental compound comprised of Ta--Si, Ti--Si, Ti--N or etc., or three elemental compound comprised of Ta--Si--N, Ti--Si--N, W--Si--N or etc are the most useful compounds.
Further, the two elemental compound takes the amorphous type of compound, for example, Ta.sub.74 Si.sub.26, which minimizes the grain bound by the addition of Si thereto in order to compensate the drawback of single transition metal layer having temperature characteristics (reactive temperature of the silicon and copper) for diffusion barrier layer from the grain boundary at a low temperature due to the polycrystalline structure.
However, the crystallization temperature of the two elemental compound rapidly decreases upon the contact with Cu, such that the temperature characteristics for diffusion barrier layer is deteriorated. In case of, for example, Ta.sub.74 Si.sub.26, it decreases from 850.degree. C. to 650.degree. C. Therefore, in order to improve the temperature characteristics for diffusion barrier layer, it requires to provide the amorphous type of three elemental compound having a high crystallization temperature due to the addition of other elements, for example, N.sub.2 and etc..
In general, the three elemental compound for diffusion barrier layer may be achieved by the following methods: a sputtering method using a target obtained by the composition rate of the three elemental compound, a reactive sputtering method forming a target of the two elemental compound for diffusion barrier layer, for example, Ta--Si, Ti--Si, W--Si and a chemical deposition method using a gaseous material and a precursor.
One of the severe problems encountered with these conventional methods lies in that according to the sputtering method of forming general three elemental compound for diffusion barrier layer, the target should be manufactured with the uniform composition rate of the three elemental compound. Further, in case of the reactive sputtering method, it is required to precisely adjust the condition gas of N.sub.2 for controlling the composition for diffusion barrier layer. Furthermore, it should be required for the chemical deposition method mentioned above to precisely control the introducing of the gaseous material. In case of the chemical deposition method for the organic metal, it is difficult to manufacture the precursor having a superior deposition characteristics and to obtain the repeatability of deposition.
Therefore, it is an object of the present invention to overcome the above disadvantages and provide a method for forming a three elemental compound for diffusion barrier layer capable of simplifying the manufacturing process thereof by depositing the two elemental compound at the initial stage and performing an out-diffusion of Si by the application of the heat treatment.
The preceding objects should be construed as merely presenting a few of the more pertinent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to both the summary of the invention and the detailed description, below, which describe the preferred embodiment in addition to the scope of the invention defined by the claims considered in conjunction with the accompanying drawings.